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Over-current and over-temperature protection element with positive temperature coefficient and preparation method thereof

A positive temperature coefficient and temperature protection technology, which is applied in the direction of resistors with positive temperature coefficients, current response resistors, conductive materials dispersed in non-conductive inorganic materials, etc., can solve the problem of high filling capacity of conductive fillers and machine blockage , the viscosity increase of composite materials and other problems, to achieve the effect of high PTC strength, good bonding force, and low room temperature resistance value

Inactive Publication Date: 2012-10-03
上海霖天功能材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Although the resistivity of the over-current and over-temperature protection element can be reduced by adding more conductive fillers, the viscosity of the protection element will increase due to the increase of fillers in this method
Moreover, the existing processing methods, such as: single-screw extrusion and twin-screw extrusion are difficult to process, and it is difficult to obtain uniformly dispersed conductive polymer composite materials; Difficult to obtain homogeneously dispersed conductive polymer composites
The main reason for this is that the filling level of the conductive filler is too high! It is therefore difficult to obtain a homogeneous distribution of conductive polymer composites, while excessively high loadings cause the viscosity of the composite to increase, resulting in considerable wear and tear on the extrusion equipment used to produce PTC polymer materials, and can often lead to machine blockages And the machine needs to be cleaned after clogging, which affects production efficiency

Method used

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  • Over-current and over-temperature protection element with positive temperature coefficient and preparation method thereof
  • Over-current and over-temperature protection element with positive temperature coefficient and preparation method thereof

Examples

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Embodiment 1

[0041] PVDF, ECTFE, and CB are proportioned according to the weight percentage of 46:6:48. First, polyvinylidene fluoride and ECTFE (a copolymer of ethylene and chlorotrifluoroethylene) are added to dimethylacetamide and heated at 20°C to 60°C. Stir and dissolve at ℃, add conductive carbon black after completely dissolved, then stir and mix the above solution by ultrasonic vibration, mix at 20℃~60℃, mixing time 15~60min, so that conductive carbon black is evenly distributed in the In the solution, a suspension with a high concentration of carbon black is formed to reach a gel state mixture, and a carbon black dispersant can be added during the mixing process to enhance the dispersion effect of carbon black. The above-mentioned mixture in gel state is extracted to remove dimethylacetamide to obtain a mixture composed of polymer and conductive carbon black. Kneading the obtained mixture of the polymer and the conductive carbon black in a heated state by means of an open mill to ...

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Abstract

The invention relates to an over-current and over-temperature protection element with a positive temperature coefficient and a preparation method thereof. The over-current and over-temperature protection element with the positive temperature coefficient consists of a conductive polymer chip, metal foils which are attached to two surfaces of the chip and flaky or lead metal electrodes which are welded to the outer surfaces of the metal foils, wherein the conductive polymer chip comprises fluorine-containing polymer matrix resin, copolymer consisting of constitutional repeating units of polyvinylidene fluoride and polyolefin and conductive carbon black; the materials are dissolved or melted with a solvent and then mixed, the solvent is removed, and the dissolved or melted materials are shaped, thermally processed, cross-linked and welded so as to finally obtain the over-current and over-temperature protection element with the positive temperature coefficient of which the conductive carbon black is uniformly distributed in the polymer matrix. Good bonding force exists between the conductive carbon black and the polymer matrix; and the element has low room temperature resistance, highPTC strength and high safety and reliability at room temperature. Meanwhile, no wearing is caused to a machine due to solution blending so as to achieve a higher percentage of the filler than that which can be generally achieved in the prior art.

Description

technical field [0001] The invention relates to a positive temperature coefficient overcurrent and overtemperature protection element and a preparation method thereof, in particular to an overcurrent and overtemperature protection element prepared from a polymer chip with a positive temperature coefficient characteristic and a preparation method thereof. Background technique [0002] In recent years, positive temperature coefficient (Positive Temperative Coefficient, PTC) over-current and over-temperature protection elements have begun to widely replace bimetal thermal protectors to protect the drive and control circuits of automotive micro-motors. Such protection elements are generally connected in series with the coils of the motor. Connected together, and it is required to have a very low resistivity at room temperature, generally less than 2 to 3Ω.cm. [0003] Under normal conditions, the protective element in series with the load in the circuit is generally kept at a lo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01C7/13H01C7/02H01C17/06H01C17/28H01B1/24
Inventor 胡定军史宇正
Owner 上海霖天功能材料有限公司
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